Cosmology, and indeed all of physics, finds itself at a crossroads. The next few years could yield answers to profound questions. What is the dark matter that makes up about 90 per cent of the matter in the universe? What is the nature of the dark energy that is causing the expansion of the universe to accelerate? What is the origin of mass? Why does our universe seem fine-tuned for the emergence of life? Are there other universes out there? The Edge of Physics takes the reader on a journey to the ends of the Earth, in search of telescopes and detectors that will help answer these questions.